const Koa = require('koa');
const app = new Koa()

const one = (ctx,next) => {
    console.log(1);
    next()
    console.log(2);
}
const two = (ctx,next) => {
    console.log(3);
    next()
    console.log(4);
}
const three = (ctx,next) => {
    console.log(5);
    next()
    console.log(6);
}

app.use(one)
app.use(two)
app.use(three)

app.listen(3000, () => {
    console.log('listening on 3000');
  })